1. Field of the Invention
The present invention relates to drink dispensers and, more particularly, but not by way of limitation, to a method and apparatus that controls agitation of a cooling fluid bath for a drink dispenser.
2. Description of the Related Art
A common type of drink dispenser used in food and/or drink service establishments is a counter electric drink dispenser. Counter electric drink dispensers include a housing defining a cooling chamber containing therein a cooling fluid in the form of a water bath. Dispensing valves mount onto the housing and communicate with a syrup line and one of a plain water line or carbonated water line disposed within the water bath for the purpose of formulating a drink from the syrup and the plain water or carbonated water. A refrigeration unit disposed within the housing includes an evaporator coil extending into the water bath, and operation of the refrigeration unit creates an ice bank about the evaporator coil. An agitator extends into the water bath and circulates the water in the water bath about the ice bank. Creation of the ice bank and circulation of the water in the water bath about the ice bank maintains the water bath at or near freezing for the purpose of cooling the syrup, plain water, and carbonated water flowing through the syrup, plain water, and carbonated water lines.
The ability of a counter electric drink dispenser to dispense drinks at or below a desired drink temperature depends upon the efficiency of the heat transfer between the syrup, plain water, and carbonated water flowing through the syrup, plain water, and carbonated water lines and the water bath, which, in turn, depends upon the capability of the ice bank to maintain the water bath at or near freezing. The capability of the ice bank to maintain the water bath at or near freezing relates to the stability of the ice bank in terms of size and shape. An ice bank that is too large or misshapen restricts the flow of water in the water bath thereabout diminishing the cooling of the water by the ice bank. An ice bank that is too small is incapable of sufficiently cooling the water in the water bath.
A factor in ice bank stability is an agitator properly agitating the water in the water bath about the ice bank. Unfortunately optimal agitation is difficult to achieve as agitators typically run continuously at a set speed. Such operation is wasteful of energy and quite often fails to achieve ice bank stability. Higher speeds achieve good circulation but frequently wash out the ice bank making it too small or misshapen. Lower speeds prevent wash out but regularly fail to prevent over or misshapen growth of the ice bank and the resulting problems. An existing solution involves operating the agitator at different speeds dependent upon the operating conditions of the counter electric drink dispenser. This does enhance ice bank stability over a set speed but such a solution still experiences the energy inefficiency involved with continuous operation of the agitator.
Accordingly, a method and apparatus that achieves ice bank stability while increasing energy efficiency will provide an improvement in counter electric drink dispensers.